1. Field of the Invention
The present invention relates to a cable protection and guide apparatus configured to accommodate, protect and guide cables and hoses.
2. Related Art
The cable protection and guide apparatus comprises a plurality of link rows connected in a longitudinal direction and pluralities of first and second connecting arms. Each link row includes a pair of link plates separately disposed in a lateral direction from each other. The link plates adjoining in the longitudinal direction are connected articulately and bendably.
Cables are accommodated within an accommodating space formed by the pair of link plates of each link row and the first and second connecting arms connecting the pair of link plates of the link row.
Known cable protection and guide apparatus includes a structure for removably attaching the connecting arm, i.e., the first or second connecting arm, to the pair of link plates. A link-side engaging portion of the link plate and an arm-side engaging portion of the connecting arm engage each other as disclosed in Japanese Patent Application Laid-open Nos. 2011-38545 (FIGS. 3 to 15), 2007-247716 (FIGS. 4 to 13), and 2007-92939 (FIGS. 4 to 7).
When the cables press the connecting arms from the inside toward the outside, the connecting arms are disengaged from the link plates by an external force applied by the cables to the connecting arm, i.e., an arm disengagement phenomenon, occurs.
Then, in order to prevent the arm disengaging phenomenon, an arrangement of disengagement preventing portions is provided in Japanese Patent Application Laid-open Nos. 2011-38545 (FIGS. 3 to 15) and 2007-247716 (FIGS. 4 to 13).
The attachment structure for removably attaching the connecting arm to the link plate includes a hinge stem (corresponds to a link-side hinge portion) provided in the link plate and a hook (corresponds to an arm-side hinge portion) provided in the connecting arm. The hook engages the hinge stem rotatably centering on a rotation axis that extends along a longitudinal direction of the apparatus. When the cable protection and guide apparatus is in a disconnected state because the connecting arms are disengaged from one link plate of the pair of link plates, the hook is liable to be disengaged from the hinge stem. External forces applied by the cables inserted into the accommodating space may rotate one of the connecting arms engaged with one of the hinge stems even when the other connecting arm is attached to one link plate of the pair of link plates.
In such a case, the disengagement preventing portions for preventing the arm disengaging phenomenon are provided on the link plate and the connecting arm.
When the cables are inserted into the accommodating space such that the hook of the connecting arm in the disconnected condition engages the hinge stem of the link plate, it is necessary to return the connecting arm to the connected condition by rotating the arm after completing the work of inserting the cable into the accommodating space. Therefore, it takes time to put the connecting arm into the connected condition.
Still further, it is necessary to increase rigidity of the disengagement preventing engage portion in order to enhance the effect of preventing the arm disengaging phenomenon. Therefore, when the disengagement preventing engage portions are provided in the hinge stem of the link plate and the hook of the connecting arm comprises the hinge structure, the hinge stem and the hook are enlarged. Thus, it is difficult to make the hinge stem and the hook smaller.
Still further, when the first connecting arm is in the connected condition and the second connecting arm is in the disconnected condition with respect to one pair of link plates and when the cables are inserted in the accommodating space in a condition in which the accommodating space is opened upward with the first connecting arm being a bottom, the accommodating space lacks integrity when inserting the cables therein. Thus, there is a problem that it takes extra time to insert the cables into the accommodating space.
Still further, when the hook is removed from or attached to the hinge stem or when an operator forcibly engages or disengages the disengagement preventing engage portions, there is a problem that parts including the engaging portions that rub with each other wear quickly.
Still further, if a gap greater than a minute gap necessary for rotation is created between the hinge stem and the hook, an abutment (or rattling) is caused between the hinge stem and the hook in rotating the connecting arm and the connecting arm is not smoothly rotated. Therefore, there are problems that wear is increased where the hinge stem abuts the hook and that it takes time to rotate the arm.
Therefore, there is a need for a cable protection and guide apparatus capable of smoother and quicker operation when the hinge structure is in the disengaged condition.
There is also a need for a smaller cable protection and guide apparatus having disengagement preventing portions that prevent the arm disengaging phenomenon.
Still further, there is a need for a cable protection and guide apparatus configured to improve durability of the attachment structure including the hinge structure for attaching the connecting arms to the link plates.